Q My PC is running Windows XP and Ubuntu 8.10 in dual-boot mode, with each OS on its own hard drive. Everything was running fine until I disabled the proprietary driver for my graphics card to try the Linux driver. The problem now is that when I get to the Ubuntu boot screen, the screen goes black and shows the message:
Out of Range; H.Frequency=12.0kHz V.Frequency=11.0Hz.
The graphics card is an ATI Radeon HD3870. Could you please tell me how I can get back into the system to enable the proprietary driver for the graphics card.
A As the X graphics server is trying to send a signal that your monitor cannot handle, it's displaying this message, but the boot is continuing behind it. While you can't see the desktop, you can always get to a text console, where you can fix things. If you don't see a boot menu when you start up, press Esc to display it when the first boot message appears on screen. There should be an option for Ubuntu marked Recovery Mode; tick this and you'll see a text menu. You can try the 'xfix' option here, which may fix the server for you, then select Resume to see whether this has worked. (Unless you've set a root password, the root option is of no use here.)
To get a shell prompt, let the standard boot proceed as normal, wait until the hard drive light has stopped flashing to know when it has finished, and press Ctrl+Alt+F1. This switches from the desktop to a virtual console, which is at a lower resolution, so your monitor should stop sulking and display it for you. Now you can log in as your normal user and fix things.
Did you uninstall the proprietary drivers or just change the settings to use the free ones? If you uninstalled them, you can reinstall from the command line with:
sudo apt-get install xorg-driver-fglrx
This should also reconfigure the card. If you don't need to install the drivers again try
sudo dpkg-reconfigure xserver-xorg
to reconfigure the card instead.